Starting device for alternating-current motors.



NO. 867,547. PATENTED 0ST. 1, 1907. W. 0. YATES. STARTING DEVICE FORALTERNATING CURRENT MOTORS.

APPLIUATION FILED OCT. 18,1905.

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W. O. YATES.

STARTING DEVICE FOR ALTERNATING CURRENT MOTORS.

APPLIOATION FILED 0OT.1B,1905.

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UNITED sTA ns PATENT OFFICE.)

WILLIAM C. YATES, OF SGHENEGTAIDY, NEW YORK, hSSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

STARTING DEVICE FOR ALTERNATING-CURRENT MOTORS Specification of LettersPatent.

Patented Oct. 1, 1907.

Application filed October 18, 1905 Serial N0- 283,247.

To all whom it may concern:

Be it known that I, WILLIAM C. YATES, a citizen of the United States,residing at Schenectady, county of Schenectady, State of New York, haveinvented certain new and useful Improvements in Starting Devices forAlternating-Current Motors, of which the following is a specification.

This invention relates to the control of alternating current motors andhas for its object the provision of a device for starting motors of theinduction type and bringing them up to running speed in a cheap, safeand efficient manner.

More specifically my invention relates to the starting of single phasemotors of the induction type. This type of motor, as is well known, willnot start from rest without the employment of special starting devices,such as auxiliary starting winding or phase splitting devices connectedin the motor circuit, or both. Devices of this character are designed tobe in circuit only for a' short period during which the motor is beingbrought up to synchronism and if left in circuit too long will becomeover-heated. Means have therefore been employed for changing theconnections so as to cut out these auxiliary starting devices. In thecase of motors with three phase windings, which are to be operated onsingle phase current, it has been the practice to use a triple-poledouble-throw switch which, when thrown in one position starts the motorwith its windings Y-connectcd with the addition of a resistancereactancedevice for producing a displaced phase at the third terminal. After themotor has been brought up to speed, the switch is thrown into theopposite position which cuts out the resistance-reactance device andplaces the motor with its windings delta-connected directly on the line.With an arrangement of this character there is nothing to prevent theoperator from throwing the switch into the starting position and leavingit there, or from throwing the switch into the running positiondirectly, without passing through the starting position. Moreover, thistype of device provides no means for throwing the switch into the offposition on failure of voltage so as to protect the motor upon thereturn of voltage to the line.

In carrying out my invention I provide instead of the knife bladeswitch, a dial switch having three arms set at an angle of 120 from eachother and biased to the off position. The connections are such that bymoving the switch arm in one direction from the off position, startingconditions are established, while by moving in the opposite directionrunning conditions are established. In connection with this device, Iprovide means whereby the arm cannot be moved from the off positiondirectly to the running position, but must first be moved to thestarting position. The

movement to the starting position removes a stop from the path of theswitch arm which is electromagnetically retained in the removedposition, and the arm may then be moved to the running position. -I alsoprovide a no-voltage magnet, the circuit of which is closed when the armreaches the starting position and means are provided in connection withthis magnet for locking the arm in running position. This magnet alsocontrols the stop device so that upon failure of voltagethe starting armis released and returned to the off position, the stop also beingreturned to the path of the starting arm.

My invention further consists in the features of construction and in thearrangement and combination of elements hereinafter set forth andparticularly pointed out in the claims annexed to and forming a part ofthis application.

In the drawings, Figure l is a plan view of a starting device embodyingmy invention; Fig. 2 is a section on the line 2 2 of Fig. 1; Fig. 3 is asection through one of the contact clips; Fig. 4 is adiagram of circuitconnections, and Figs. 5 and 6 show respectively the connections of thewindings and the resistance-reactance for starting and running.

Referring to the drawings, 1 is an insulating base of slate or soapstone provided with three sets of contacts having a controlling memberpivoted for engagement therewith. This controlling member 2 is pivotedat 3 and provided with three arms 4, 5 and 6 arranged 120 apart one ofthe arms being provided with a handle 2 for operating the same. Each armis provided with three contact clips 7, 7 and 7, 8, 8 and 8 ,and 9, 9 9,which are electrically connected together but insulated from the arm andfrom the contacts on the other arms. The contacts 7, 8, and 9 engagerespectively, with the conducting segments 10, 11 and 12, while theremaining contacts engage respectively with the insulating segments 10,11, 12 and 10, l1 and 12, as shown when the controlling arm is in theoff position. The contacts engage with these segments but upon themovement of the arm either to the left or to the right, the contactspass out of engagement with the insulating segments while the contactwith the conducting segments continues. Contact studs 13, 14, 15. 16,17, 1s, and 13', 14 15 16, 17 and 18' are arranged one opposite each endof each insulating segment so that as the arm is moved off theinsulating seg ment in either direction from the center, it will moveinto engagement with the studs, and there will thus be electricalconnections between the studs and the conducting segment of eachsection, that is, when the arm is moved to the left the segment 10 willbe electrically connected with the studs 13 and 13 and similarconnections will be made in the other sections. The

- s rin 19 C06 ieratin with the pins 20 in the base and I a I g on thearm gives the arm a bias to the off or central position. g

In my device as herein shown, the connections are such that as the armis moved to the left the starting conditions are established, while amovement in the opposite direction establishes connections for running.In order, therefore, to prevent the movement of the arm to the rightbefore it has first been moved on to the contact studs to the left, Iprovide the following mechanism: A lug 21 is mounted-upon the 'arm 5 andarranged to be engaged by the stop piece 22 having at its extremity ashoulder 23. This stop piece is secured to the core armature 24 of theno-voltage magnet 25 and a guide screw 26 is secured to the magnet forguiding the stop piece in its up and down movement. At the upperextremity of the core armature 24 is a rod 26 provided with a bridgingcontact 27 adapted to close the circuit between contacts 28 and 29when'it reaches the outer and upper limit of its. movement. A latch 30is pivoted at 31 and provided with a hook for engaging the pin 32 on thearm 4 when the latter is moved to running position. This latch isprovided at its end opposite the hook with a hub portion which forms aguide bearing for the rod 26. A spring 33 normally forces the hookportion of the latch downward so as to engage the pin 32, and a collar34 rigidly secured to the rod 26 engages the hub portion of the latch asit travels downward to move the hook upward against the tension of thespring.

The armature 24 and magnet 25 are so arranged'that the former will beengaged by the arm 5 and as the controlling arm is moved -to the left,the stop 22 is carried up with the armature so as to be out of the pathof the lug 21. The armature is forced upward by the arm 5 until thecontacts 28 and 29 are bridged, closing the circuit otthe magnet 25,which upon being energized holds the armature 24in raised position andthereby keeping the circuit closed and allowing the hook portion of thelatch to descend so as to engage the pin 32 when the arm is moved torunning position. The arm may now be moved to running position and therelatched. Uponiailure of voltage the armature will drop, opening thecircuit and bringing the stop piece again into the path of the lug 21.As the armature drops the collar 34 engages the latch, trips the sameand allows the controlling arm to return to the off position.

I have shown my device in connection with a motor having a three phasewinding to be operated by a single phase current, and in order that themotor may be started from rest under these conditions a split phasedevice is employed. The starting connections are shown in Fig. 5 inwhich the motor windings A, B, and C are V-connected with the resistanceD and a reactance E connected across the line L L so as to produce adisplaced phase, this form of connection being well known in the art.'After the motor gets up to speed, the resistance-reactance is cut outand the windings are delta connected across the line as shown in Fig. 6.The circuit connections whereby my switch brings about the change fromstarting to running connections are shown in Fig. 4. With thecontrolling arm moved to the left into starting position, current passesfrom the line L to contact 28 and also by conductor 35 to segment 12,thence to stud 17, conductor 36 through the reactance E, conductors 37and 38 to winding B at 4, thence through the winding to 5 and conductor39 to studs 18 and 13. The current then passes to segment 10 across thearm 4 and thence through conductor 40 to winding 0 at 3, thence throughthe winding to 2 and through conductor 41 and studs 16 and 15 to segment11, thence by conductor 42 to the line L. Current also passes from stud17 through the winding A to the center of the V connection at 1. Withthe switch in this position, the ends 1, 3, and 5 of the windings areconnected at a common neutral point as shown in Fig. 5. When the arm ismoved to the right the arrangement is as shown in Fig. 6: the windingsbeing delta connected across the line and the resistance-reactance D Ecut out, the direction of current will then be as follows:from the lineL through conductor 35 to segment 12, thence to stud 18, stud 17,conductor 43 to the winding A at 6, through the winding to 1 andconductor 44 to stud 16, thence through the arm 5 to segment 11 and outto line through conductor 42, the winding A being in parallel with thetwo windings B and C which are in series with each other. Thisestablishes running conditions of the motor which are maintained untilthe arm is returned to the off position through failure of voltage. Themagnet 25 is connected across the line L L and in shunt to the motor.

While I have shown my device in connection with a particular type ofmotor, namely, a three-phase motor to be operated by a single phasecurrent, it should be understood that I do not limit my invention in itsapplication to this or any other type of motor except in so far as it islimited by the scope of the claims annexed to and forming a part of thisapplication.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is,

1. The combination with an alternating current motor having differentconnections of the windings for starting and running, of a switch biasedto the 0G position for changing said connections, and a no-voltagemagnet con trolled by the switch for holding the latter in runningposition.

2. The combination with a single phase induction motor, of phasesplitting devices for starting the same, a switch biased to the offposition and arrangedto connect the motor for starting or running, and ano-voltage mag net controlled by the switch for holding the latter inrunning position.

3. The combination with an alternating current motor having differentconnections for starting and running, of a switch therefor biased to anofl. position between the starting and running position, a novoltagemagnet for holding the switch in running position, and means controlledby said magnet for preventing the moving of the switch into one of theoperative positions without first passing through the other operativeposition.

4. The combination with a single phase induction motor of phasesplitting devices for starting said motor, a switch biased to the oifposition and arranged to connect the motor for starting or running, ano-voltage magnet for bolding the switch in running position, and meanscontrolled by said magnet for preventing the movement of the switch intothe running position without first passing through the startingposition.

5. The combination with an alternating current motor having differentconnections for starting and running, of a. switch biased to the offposition for changing said connections, :1 no-voltage magnet for holdingthe switch in running position, a stop controlled thereby'for preventingthe movement of the switch from the off position directly to the runningposition, and means for removing said stop as removed and the circuit ofsaid magnet closed by the move- 10 the switch is moved to startingposition; ment of said switch to starting position.

6. The combination with an alternating current motor In witness whereofI have hereunto set my hand this having different connections forstarting and running, of a 17th day of October, 1905 switch biased tothe off position for changing said connections, a no-voltage magnet forholding the switch in run WILLIAM YATES ning position, a stop controlledthereby for preventing the Witnesses: movement of the switch arm fromthe off position directly BENJAMIN B. HULL,

to the running position, and means whereby said stop is HELENORFORD.

